No Grades?

I found some articles on schools without grades, since a lot of my students became interested in this after I mentioned it in class last week.  I found some research in my quick search tonight, but it was all done in the 1960's.  So, I'll try to find some time this week to see if any new studies have been done on the effects of this type of progressive education on students' future success in schools (college acceptance).

The following is from an NPR story a few years ago.
http://www.npr.org/templates/story/story.php?storyId=4618720

Here's one that takes the philosophy a little far (in my opinion).  
http://seattletimes.nwsource.com/html/localnews/2003645914_unschooled01m.html

Many Law schools do not have grades, like Yale: 

http://www.law.yale.edu/admissions/4881.htm